maildap documentation questions

In the maildap README, the two example configurations make use of KINDS
and SYNTAXES that are not listed in the KNOWN KINDS and KNOWN SYNTAXES
lists (ie; "request", "owner", "host", "forward-to-host", etc.).
1) May I assume that their presence in the examples implies that they
are indeed legitimate options even if they did not appear in the KNOWN
lists? Are there others available?
2) What are the usage definitions for these "unknown" kinds and
syntaxes?
3) The order of KINDS and SYNTAXES in the examples does not match the
order shown in the general ATTRIBUTE definition.
The initial Configuration File paragraph would be more helpful if it
stated the specific groups of definition statements required/available,
and their required order. Is the required order the order shown in the
examples?
I see a paragraph on ATTRIBUTE definitions. I see a paragraph that
mentions Search Bases, but doesn't clearly define them (pointing to some
"example above" - which? - are you assuming the LDAP URL search base
parameter?). I see nothing about the SEARCH definitions, explicitly. I
see nothing explicitly about "group-classes".
Lastly, I see in some of the LDAP URLs both "=" and "==" without any
explanation. Are they different or are they equivalent or are they
simply typos?
Thank you.